1. Field of the Invention
The present invention relates to a ring speed detector that is intended to detect the rotating speed of a ring and used for the antilock brake or the like of an automobile.
2. Discussion of Prior Art
Conventionally, as a ring speed detector of this type, there has been provided a detector that is provided with a magnetic sensor fixed to the fixed side of an inner ring and an outer ring and a magnetic ring arranged on the rotating side so as to face this magnetic sensor and detects the rotating speed of the ring by detecting a magnetic field varied in accordance with the rotation of this magnetic ring by means of the magnetic sensor.
The ring speed detector of the above type has conventionally been arranged independently of a seal device for sealing a space between the inner ring and the outer ring with respect to the outside. This accordingly requires a special-purpose space and disadvantageously leads to a lack of compactness. The above arrangement also requires certain consideration for the dispositional relation of the detector relative to the other components that constitute the rings and accordingly leads to the problem that the workability in the assembling stage is not good.
Accordingly, the object of the present invention is to provide a compact ring speed detector capable of saving space around the rings and improving the workability.
In order to achieve the object, there is provided a ring speed detector for detecting a relative rotating speed between an outer ring and an inner ring by means of a magnetic sensor in association with an opposite magnetic ring, wherein one of the outer ring and the inner ring is rotatable while the other is stationary, the magnetic ring is fixed to the rotatable ring and the magnetic sensor is fixed to the stationary ring,
the magnetic ring and the magnetic sensor being integrated with a seal device for sealing a gap between the inner ring and the outer ring.
According to the present invention, the magnetic ring and the magnetic sensor are integrated with the seal device for sealing the gap between the inner ring and the outer ring. This arrangement can improve the compactness and the workability in the assembling stage.
In one embodiment of the present invention, the seal device has the magnetic ring and the magnetic sensor built-in.
According to the above construction, the seal device has the magnetic ring and the magnetic sensor built-in. This arrangement can enable the space saving around the rings.
In one embodiment of the present invention, the magnetic ring is fixed to a rotatable member of the seal device for sealing the gap between the inner ring and the outer ring, and the magnetic sensor is fixed to a stationary member of the seal device.
According to the above construction, the magnetic ring and the magnetic sensor are integrated with the seal device by fixing the magnetic ring to the rotatable member of the seal device and fixing the magnetic sensor to the stationary member. This arrangement can enable the space saving around the rings and improve the compactness and the workability in the assembling stage.
In one embodiment of the present invention, the magnetic ring and the magnetic sensor are arranged in a space where the rotatable member and the stationary member of the seal device face each other.
According to the above construction, the magnetic ring and the magnetic sensor are arranged in the space where the rotatable member and the stationary member of the seal device face each other. This arrangement can enable the space saving around the rings and improve the compactness and the workability in the assembling stage.
In one embodiment of the present invention, a seal portion of the seal device is provided on both sides of the portion where the magnetic ring and the magnetic sensor face each other.
According to the above construction, the sea portion is provided on both sides of the oppositional portion where the magnetic ring and the magnetic sensor face each other. This can prevent water from intruding into the bearing inwardly of the magnetic sensor and prevent lubricant from leaking out of the bearing.
In one embodiment of the present invention, the magnetic ring and the magnetic sensor face each other obliquely with respect to the axis of rotation of the inner ring and the outer ring.
According to the above construction, the magnetic ring and the magnetic sensor, which face each other obliquely with respect to the axis of rotation of the inner ring and the outer ring, can be reduced in the radial dimension and compacted.
In one embodiment of the present invention, the stationary member of the seal device concurrently serves as a magnetic path of the magnetic sensor.
According to the above construction, the stationary member of the seal device concurrently serves as the magnetic path (yoke) of the magnetic sensor, and this can reduce the number of components for the achievement of compacting.
In one embodiment of the present invention, a seal portion constructed of a slinger and a seal lip to be brought in sliding contact with the slinger is provided axially outside the oppositional portion where the magnetic ring and the magnetic sensor face each other, and a main seal portion is provided between this seal portion and the oppositional portion.
According to the above construction, the additional seal portion constructed of the slinger and the axial seal lip is provided outside the main seal portion. This arrangement can improve the sealing performance and improve, in particular, the waterproof performance of the sensor portion.
In one embodiment of the present invention, the seal device is constructed of a rotatable member and a stationary member,
the magnetic sensor is fixed to the stationary member, the magnetic ring is fixed to the rotatable member, and the magnetic ring is covered with a nonmagnetic elastic member.
According to the above construction, the magnetic ring is covered with the nonmagnetic elastic member. This arrangement can prevent the magnetic foreign material such as iron powder from adhering to the magnetic ring and prevent the occurrence of noises.
In one embodiment of the present invention, the stationary member and the rotatable member constitute a labyrinth seal, and
the nonmagnetic elastic member is provided with an axial lip that extends in the axial direction and comes in sliding contact with the stationary member and a main lip that extends in the radial direction and comes in sliding contact with the stationary member.
According to the above construction, the labyrinth seal constructed of the stationary member and the rotatable member, the axial lip and the main lip can provide three-point sealing, and this can reliably prevent water from intruding into the bearing.
In one embodiment of the present invention, the nonmagnetic elastic member is provided with an auxiliary lip that comes in sliding contact with the stationary member inside the main lip.
According to the above construction, the auxiliary lip brought in sliding contact with the stationary member inside the main lip is provided, and this can further improve the waterproof performance.
In one embodiment of the present invention, the stationary member is made of austenite-based stainless steel, copper or aluminum.
According to the above construction, the stationary member for fixing the magnetic sensor is made nonmagnetic with the material of austenite-based stainless steel, copper or aluminum. This arrangement can improve the magnetic detection accuracy of the magnetic sensor.
In one embodiment of the present invention, the seal device is constructed of a rotatable member and a stationary member,
an axial lip that extends axially outwardly of an axial outer surface of the rotatable member and comes in sliding contact with an axial inner surface of the stationary member is provided,
the magnetic ring is fixed to an axial inner surface of the rotatable member, and the magnetic sensor is fixed to an axial outer surface of the stationary member.
According to the above construction, the magnetic ring is fixed to the inner surface of the rotatable member, and the axial lip is fixed to the outer surface of the rotatable member. This arrangement can magnetize the magnetic ring from inside the rotatable member without being obstructed by the axial lip and facilitate the manufacturing.
In one embodiment of the present invention, the rotatable member is a magnetic body.
According to the above construction, the rotatable member to which the magnetic ring is fixed is magnetic, and this can increase the magnetic force of the magnetic ring.
In one embodiment of the present invention, the magnetic ring and the magnetic sensor face each other in the radial direction.
According to the above construction, the magnetic ring and the magnetic sensor face each other in the radial direction, and this can reduce the axial dimension and achieve compacting in the axial direction.
In one embodiment of the present invention, the seal device is constructed of a rotatable member and a stationary member,
the magnetic ring is fixed to the rotatable member, the magnetic sensor is fixed to the stationary member and there are provided
a main lip that is fixed to the rotatable member or the stationary member and seals a path between the rotatable member and the stationary member, a first auxiliary lip located inside the main lip, an axial lip located outside the main lip and a second auxiliary lip located outside the axial lip.
According to the above construction, the second auxiliary lip located outside the axial lip is provided in addition to the main lip, the first auxiliary lip and the axial lip, and this can improve the sealing performance. The second auxiliary lip prevents muddy water from directly splashing on the axial lip, and this can improve muddy water resistance.
In one embodiment of the present invention, the inner ring is rotatable, and
the second auxiliary lip is fixed to the rotatable member fixed to the inner ring and extends radially outwardly to seal a path between the rotatable member and the stationary member.
According to the above construction, the second auxiliary lip is fixed to the rotatable member fixed to the rotatable inner ring located, and therefore, a centrifugal force in the rotating stage presses the second auxiliary lip against the stationary member located radially outside. This arrangement can improve the sealing performance in the rotating stage.
In one embodiment of the present invention, a cover member for covering the magnetic sensor is provided,
the cover member has an inclined surface inclined relative to the axis of rotation of the outer ring and the inner ring and
a harness connected to the magnetic sensor is projecting from the inclined surface.
According to the above construction, the harness is made to project from the inclined surface of the cover member of the magnetic sensor, and this can widen the harness outlet width.
In one embodiment of the present invention, the seal device is constructed of a rotatable member and a stationary member,
a magnetic ring and a magnetic sensor are fixed to an axial oppositional portion where the rotatable member and the stationary member face each other, and
a cover member for covering the magnetic sensor has
one or more ring-shaped projections that form a labyrinth in a path that extends in the radial direction between the rotatable member and the stationary member.
According to the above construction, the cover member for covering the magnetic sensor fixed to the stationary member has the ring-shaped projection, and this ring-shaped projection forms the labyrinth in the path that extends in the radial direction between the stationary member and the rotatable member. This arrangement accordingly obviates the need for forming an axial lip for sealing the path in the radial direction on the rotatable member. Therefore, the axial lip does not become an obstacle in magnetizing the magnetic ring fixed to the radial portion of the rotatable member, allowing the manufacturing to be facilitated.
In one embodiment of the present invention, the seal device is constructed of a rotatable member and the stationary member,
the magnetic ring is fixed to the rotatable member, the magnetic sensor is fixed to the stationary member and
at least part of the magnetic sensor is arranged in a hole formed through the stationary member.
According to the above construction, at least part of the magnetic sensor is arranged in the hole formed in the stationary member. This arrangement can promote the space saving and provides excellent mountability in the case of a small space.
In one embodiment of the present invention, all seal lips are fixed to the stationary member to which the magnetic sensor is fixed.
According to the above construction, all the seal lips are fixed to the stationary member to which the magnetic sensor is fixed, and this simplifies the structure.
In one embodiment of the present invention, the stationary member has a removable cover metal fitting, and the magnetic sensor is mounted on the cover metal fitting.
According to the above construction, the magnetic sensor is mounted on the removable cover metal fitting, and this facilitates the replacement of the magnetic sensor.